“Criticism is criticism,” says Jonathan Gold, who writes about food for The Los Angeles Times. “An aria is like a well-cooked potato.” To which I can only say: Amen. Creative inspiration can be found in a great variety of human pursuits, and criticism is the name we give to the act of identifying and sharing it. A painting is, in that respect, like a poem. A well-written book is like a well-built shelf. A newspaper column is like a documentary film.

“City of Gold,” directed by Laura Gabbert, is an affectionate portrait of Mr. Gold, a genial walrus of a man with a graying ginger mane and a gentle, gaptoothed smile. The film accompanies him in his green pickup truck as he patrols the streets of Los Angeles, pointing out the best places to find fiery Southern Thai stews and sublime Oaxacan moles. We sit in on editorial meetings and peek over his shoulder as he writes on his laptop at the dining room table. Colleagues and expert witnesses are summoned to pay tribute to his genius and annotate his quirks. We spend some time with Laurie Ochoa, his wife and erstwhile editor, and their two children. We learn about Mr. Gold’s childhood, his early career, his Pulitzer Prize. Ms. Gabbert, in other words, follows the usual documentary recipe.

But “City of Gold” transcends its modest methods, largely because it connects Mr. Gold’s appealing personality with a passionate argument about the civic culture of Los Angeles and the place of food within it. His enthusiasm and generosity of spirit stand in definitive rebuke to the myth that critics are crabbed, hostile, pleasure-hating creatures. Rejecting the restaurant reviewer’s customary anonymity, Mr. Gold is warmly received by cooks, servers and restaurateurs, many of whom are grateful for his positive reviews.

This is more than boosterism. Mr. Gold, whose first love was music — he studied classical cello and fell in love with punk rock — blends his search for culinary excellence with advocacy and ethnography, and writes in the service of a humane, multicultural vision of urban life. While he eats in and writes about high-end restaurants and ambitious, would-be celebrity chefs, his heart is in the vernacular gastronomy of immigrant and working-class neighborhoods. He is a Walt Whitman of taco trucks, hot-dog stands and pho parlors, of unassuming storefront and strip-mall joints that bring the flavors of the world to Southern California.

Before becoming a full-time food writer, Mr. Gold resolved to eat at every restaurant on Pico Boulevard, a 15-mile thoroughfare that runs from downtown Los Angeles in the east to Santa Monica in the west. The project confirmed what he had already suspected about his native city, whose geography and demography created a complex and constantly shifting mosaic of cuisines: Los Angeles is an incubator of cultural and commercial variety. The decentered sprawl of the city tends to disorient visitors from the opposite coast, but real estate prices are less than ruinous, and the supply of hungry people is limitless.

Not that Los Angeles is any kind of utopia. Mr. Gold remembers both the Watts riots of 1965 and the unrest that followed the 1992 acquittal of the police officers who had beaten Rodney King. He is likened at one point to Raymond Chandler, another writer who explored the hidden, unglamorous corners of a city too often besotted by its own hype. And there is an intriguingly melancholy strain in both his writing and in this mostly celebratory film. Great cities are places of constant change, hectic loss, occasional violence and painful division. To live in one is to grapple, every day, with ambivalence and disappointment, with constant reminders of how the pursuit of perfect happiness (or even reasonable contentment) can fail.

In the face of that reality, Mr. Gold finds intimations of perfection — meals, dishes, single bites that sustain his faith in Los Angeles and, by implication, in humanity. “City of Gold” is a lovely testament to that faith, worth attending to even if you think you have no interest in food, California or criticism.